In the Negev Desert, an international crew simulates life on Mars in Last Exit: Space (Henning Brümmer/discovery+)

This curious documentary opens with a monologue by none other than filmmaker Werner Herzog (who serves as executive producer), who, narrating in his signature droll manner, proclaims humanity has long dreamt of traveling to the stars. While the days of Mars colonies are now closer than ever to becoming reality, both Herzog and his son, writer/director Rudolph Herzog, argue there are still considerable obstacles in the way.

The film profiles scientists, engineers, a former astronaut, a futurologist, and a scientist Werner calls a “planet hunter.” Some argue that humanity’s expansion to other worlds in our galaxy or beyond it isn’t an option but a necessity as well as an inevitability, given climate change and other grave threats. The interviewees represent a variety of nationalities and ages and encompass both men and women. They never cross paths with one another, but the interviews flow logically from one to the next.

The focus doesn’t linger on any one subject for a lengthy amount of time, yet many leave strong impressions. One of the first interviewees is a high school-age space enthusiast, Anna Olsen, who belongs to a DIY club in Copenhagen whose members build and launch rockets. The group’s goal is to be the first civilian outfit to complete human spaceflight, and in one scene, Olsen reclines in a rocket and stares straight up at the camera, at which point images of floating hands and Mars’s landscape appears, as if taking us into her fantasies.

The approach Rudolph takes throughout is to emphasize his subjects’ quirks or eccentricities. Such is the case with a space anthropologist, Taylor Genovese, whom we are introduced to as he is running full-tilt through a real-life abandoned missile site in an undisclosed location. (It’s never clear why, though perhaps it’s intended to represent being trapped in a depressing corporate facility on another planet.) Another interviewee who comes across as a bit odd is space sexologist Simon Dubé, whose unidentified assistant spends the entirety of the segment quietly floating in a sensory deprivation tank, with Dubé spinning him around at one point.

Rudolph may have been trying to liven up material that he feared would be too dry for viewers, or maybe these scientists and experts are really like this. Either way, the film never lets their on-screen antics distract too much from their compelling, often pointed opinions about the challenges of interstellar colonization. Meanwhile, the constant push and pull between whimsy and reality in many of these interviews is also happening with the film as a whole as the Herzogs travel down roads of scientific development that border on speculative fiction, only to double back and remind us there are intermediate steps mankind hasn’t yet solved.

Last Exit: Space contains some moments of genuine wonder, including a look at microscopic organisms called tardigrades, which resemble tiny, multilegged bears. According to one expert, these creatures could hold the secret for helping mankind better adapt to the treacherous conditions of outer space via gene-splicing. At a visit to a Maryland-based medical center, doctors engage in a cutting-edge experiment to place a simulated wounded body into suspended animation by replacing blood with cool saline. The implications of this technology for space travel aside, the scene stands out because of the chaotic, emergency room-style drill, which provides a jolt of adrenaline that the film otherwise lacks much of.

It’s worth noting that the film benefits from having the elder Herzog on board as narrator. In descriptions about how unglamorous colonizing Mars would be in reality, the way he talks about hypothetical colonists hunkered down in radiation-proof bunkers “enjoying drinks of recycled urine” sounds merely matter-of-fact. The same goes for a journey to outer Planaltina, Brazil, which is the home of the followers of Vale do Amanhecer, who believe they are descended by aliens who visited the Earth 32,000 years ago. Even when he discusses how the followers receive energy from an invisible, hovering mother ship, it seems just as credible as any of the other scientific theories, thanks to Herzog’s deadpan delivery,

Last Exit: Space may appeal to Werner Herzog diehards due to its similar predilection toward eccentrics. Still, when compared to many of his own credited documentary efforts, it suffers by not being nearly as personal, soulful, or visually interesting. (I would argue that just the opening of Into the Inferno (2016) is more memorable than any shot in this film.) Yet it’s entertaining, and, if nothing else, splashes much-needed cold water on anyone who thinks we can simply colonize another planet if/when Earth becomes uninhabitable.